Flu Vaccine Research: Overcoming 'Original Sin'

Scientists studying flu vaccines have identified ways to overcome an obstacle called "original antigenic sin," which can impair immune responses to new flu strains.

Original antigenic sin (OAS) is a situation where the immune system is fighting with obsolete weapons and has trouble adapting. After encountering one viral strain, and then a new one that is related to the first, the immune system can respond by making antibodies against the first strain, resulting in a less effective defense.

Researchers at Emory Vaccine Center have demonstrated in experiments with mice that OAS can be overcome by using a vaccine additive called an adjuvant, or by repeated immunization with the second viral strain. The results were published this week in Proceedings of the National Academy of Sciences (PNAS).